In networks using software defined networking (SDN), one or more network controllers may manage the control plane of network devices, such as switches, bridges and routers. The network controller may also manage the data plane of the switches by providing flow rules to the switches. The flow rules may have various attributes, such as match fields, meters, go-to instructions, and actions. A flow is a set of packets sharing common attributes. For example, a flow may be defined by layer 2 or link layer information, such as source or destination MAC address; layer 3 or network layer information, such as source or destination IP address; or other information such as frame type, class of service indicator, or frame control information. The match fields of a flow rule establish a corresponding flow by setting the attributes shared by packets of the flow. During operation, if a match field is met by a packet then the network device performs the action on the packet. Match fields may include various criteria, such as source or destination IP or MAC address, port numbers, transport protocol type, frame type, class of service indicators, or frame control information. Actions may include various operations that the switch can perform on packets, such as forwarding the packet to a specified port, dropping the packet, or forwarding the packet to the controller.